The 4th International Workshop on Carcinoembryonic Antigens/Pregnancy Specific Glycoproteins (CEA/PSG) was held at the Deaconess Hospital in Boston from August 22nd to 25th 1993 and covers 2.5 days of scientific sessions. The workshop was organized by Drs. Peter Thomas and J. Milburn Jessup both of the Deaconess Hospital. The workshop is designed both to update scientists working in the field and to introduce new scientists to this area of research. There are approximately 70 registered participants from the United States, Canada, Japan, Russia, Germany, England and Sweden. Participation is by invitation only. Thirty one oral presentations and nineteen posters are planned. The workshop includes two general lectures on adhesion molecules (by Dr. Uris Rutishauser) and GPI linked membrane proteins (by Dr. D. Lublin) respectively. Specific topics include (1) Structural studies on individual members of the CEA/PSG gene family including C-CAM and their relationship to the immunoglobulin supergene family. (2) Identification of related proteins in non-human species and their evolution. (3) Regulation of expression of the CEA/PSG gene family members. (4) Function of the gene family members as cell adhesion molecules and their role in cancer metastasis. (5) The structure of the CEA/PSG gene complex on chromosome 19. (6) Antibodies to the gene family members and their use in functional studies and diagnosis.